GAST: Gas tests at the GAs permeable Seal Test – Successes and lessons learned (Grimsel Test Site, CH)
Bibliographic record
Abstract
The degradation of organic substances and metal components is expected to generate gases in radioactive waste repositories. Therefore, gas-permeable plugs and seals concepts have been developed to manage gas pressure development while ensuring the containment of radionuclides and other non-radioactive contaminants.The Gas permeable Seal Test (GAST) is an international project aimed at testing the feasibility and functionality of a gas-permeable seal under realistic scale and boundary conditions. The seal is made of a mixture of 80/20% sand/bentonite mixture and emplaced in the Grimsel Test Site (Switzerland).After a decade of progressive seal saturation and pressurisation with water, gas flow tests were carried out between May 2022 and August 2023. Noble gases (i.e. He, Ar, Xe) were used as tracers of gas transport through the seal section of the experiment.Consolidated interpretation of the results indicate that the gas path developed quickly through the seal (end-to-end-flow). Furthermore, the presence of the injected gas tracers both at the extraction point and in gas samples taken from inside the emplaced sand/bentonite layers demonstrated the existence of a gas phase within the seal. Finally, the absence of measurable gas leaks within the tunnel further confirmed the overall functionality of the seal system. AcknowledgementsGrimsel Test Site Staff for support onsiteSolexperts for hardware components, support in field and with measurementsEntracers and Hydroisotop for onsite and offsite gas analyses
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.015 | 0.006 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".